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Compiled function different from uncompiled version? HOW?!

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31664] Compiled function different from uncompiled version? HOW?!
  • From: Benjamin Lotto <benNOSPAMlotto at yahoo.com>
  • Date: Fri, 23 Nov 2001 05:46:49 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

I'm trying to write some code to draw pictures of Julia sets.  The 
following code does what I want until I try to compile it.  Then, all of 
a sudden, I get a different (and wrong) answer!  What's going on?  Am I 
misusing Compile?

The following uses Mathematica version 3.0.1 on MacOS 8.6.

Help!!!

In[1] := Julia[z_,c_]:=
  Module[{test=Max[2.,Abs[c]]},
    Length[FixedPointList[(#^2+c)&,z,50,SameTest->Function[Abs[#1]>test 
]]]];

In[2] := compiledJulia=
  Compile[{{z,_Complex},{c,_Complex}},
    Module[{test=Max[2.,Abs[c]]},
      Length[FixedPointList[(#^2+c)&,z,50,
          SameTest->Function[Abs[#1]>test ]]]]];

In[3] := z = 0.984224 + 0.439194 * I; c = 0.361564 + 0.743827 * I;

In[4] := Julia[z,c]

Out[4] := 4

In[5] := compiledJulia[z,c]

Out[5] := 1

-- 
Benjamin Lotto <benNOSPAMlotto at yahoo.com>
(Remove NOSPAM to reply.)


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